Bland-Altman plots of difference in caffeine (mg/day) and beverage (cups/day) intakes between the food frequency questionnaire (FFQ) and the 24-hour dietary recall (24HDR) in the BioCycle Study, 2005–2007. The dotted line in each graph represents the mean difference between the FFQ and the 24HDR on the original scale; solid lines represent relative limits of agreement on the logarithmic scale. One cup = 237 mL. Coffee includes all types but “not lattes or mochas.” Coffee drinks/cocoa includes “latte, cappuccino, mocha, or hot chocolate.”

Caffeinated coffee intake reported in the 24-hour dietary recall (24HDR) (squares) at the clinic visit compared with that reported in the daily diary (circles) on the day preceding the clinic visit over 2 menstrual cycles (n = 258) (cycle 1, top; cycle 2, bottom) in the BioCycle Study, 2005–2007. The 24HDRs were conducted 4 times per cycle with visits timed via fertility monitors to relevant menstrual cycle phases: day 2 of menstruation, midfollicular phase, day of ovulation, and midluteal phase (approximately corresponding to days 2, 7, 14, and 22 of a 28-day cycle). One cup = 237 mL. Coffee includes all types but “not lattes or mochas.” Coffee drinks/cocoa includes “latte, cappuccino, mocha, or hot chocolate.”